Two novel bacteria, designated strains Gsoil 634T and Dae 20T, were isolated in South Korea from soil of a ginseng field and freshwater sediment, respectively and were characterized by a polyphasic approach to clarify their taxonomic positions. Phylogenetic analysis based on 16S rRNA gene sequences indicated that, although they probably represented two distinct species (indicated by a sequence similarity of 96.6 %), both strain Gsoil 634T and strain Dae 20T belonged to the genus Sphingomonas and were most closely related to ‘Sphingomonas humi’ PB323 (97.8 % and 96.7 % sequence similarity, respectively), Sphingomonas kaistensis PB56T (96.8 % and 96.7 %), Sphingomonas astaxanthinifaciens TDMA-17T (96.6 % and 95.4 %) and Sphingomonas jaspsi TDMA-16T (95.6 % and 95.8 %). For both novel strains, the major ubiquinone was Q-10, the major polyamine was homospermidine, the major cellular fatty acids included summed feature 7 (C18 : 1ω7c, C18 : 1ω9t and/or C18 : 1ω12t), C17 : 1ω6c and C16 : 0, and the polar lipids included sphingoglycolipid. These chemotaxonomic data supported the affiliation of both strains to the genus Sphingomonas. However, the DNA–DNA relatedness value between strain Gsoil 634T and ‘Sphingomonas humi’ PB323T was 31 %. Moreover, the results of physiological and biochemical tests allowed the phenotypic differentiation of strains Gsoil 634T and Dae 20T from established members of the genus Sphingomonas. Based on these data, the two isolates represent two novel species in the genus Sphingomonas, for which the names Sphingomonas ginsengisoli sp. nov. (type strain Gsoil 634T = KCTC 12630T = DSM 18094T = LMG 23739T) and Sphingomonas sediminicola sp. nov. (type strain Dae 20T = KCTC 12629T = DSM 18106T = LMG 23592T) are proposed.

†

These authors contributed equally to this work.

The GenBank/EMBL/DDBJ accession numbers for the 16S rRNA gene sequences of strains Gsoil 634T and Dae 20T are AB245347 and AB258386, respectively.

A supplementary figure is available with the online version of this paper.

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